Sequential switch



Patented Feb. 3, 1953 UNITED STATES ATENT OFFICE SEQUENTIAL SWITCH Philip C. Neizel, Philadelphia, Pa., assignor to General Electric Company, a corporation of New York 9 Claims.

The invention relates to sequential switches, particularly eld discharge switches that are closed when the main eld switches are opened and vice versa.

One object is to provide an improved form of sequential switch motion converting mechanism capable of converting the closing and opening movement for one pivotally mounted switch respectively into opening and closing movement for another coaxially pivotally mounted switch. This enables standardswitch parts to be used in sequential switching service as,- for example, field switching service where two standard switch units having a common reciprocating operating member may be spaced apart to constitute the main eld switch with another standard discharge switch unit interposed therebetween to form a triple-pole eld discharge type of breaker. In this way standard movable and cooperating switch contacts, as well as standard mounting bases, arc chutes, and a common reciprocating operating member can be employed for all poles.

Another object is to provide for overlapping the closing and opening of the sequential switches so that each switch is always closed before the other is opened. This feature is of importance where a eld discharge breaker is used with synchronous machines to prevent excessive voltage being built up in the eld winding in case the discharge resistor is disconnected therefrom while the field is open-circuited.

Other objects and advantages of the invention will appear in the following description of the accompanying drawings in which Fig. l is a perspective view of a triple-pole iield discharge type circuit breaker embodying the reverse `motion converting improvements of the present invention in a preferred form; Fig. 2 is an enlarged sectional view of the movable and cooperating switch contacts indicating the extended wiping action thereof that enables switch closing and opening overlapping to be obtained; Fig. 3 is a iront View of the relatively stationary contacts shown in Fig. 2 indicating the standard multiple finger construction thereof; Fig. 4 is a side View partly in section of the intermediate eld discharge unit of the triple-pole switch shown in Fig. l with the parts in the iield discharge circuit closing position; Fig. 5 is a similar view with the eld discharge switch unit in the open position; Fig. 6 is a partial front view of the iield discharge switch motion converting mechanism shown in Figs. 4 and 5 more clearly illustrating the interrelation of the motion reversing parts; Fig. 7 is a schematic view of the 3-pole switch shown in Fig. l with the eld circuit and discharge connections thereto diagrammatically illustrated with the discharge circuit open and the field circuit closed; and Fig. 8 is a similar schematic view showing the intermediate field discharge switch in the closed position and the two main eld switches in the open position.

As shown in Fig. l, the triple-pole eld discharge type breaker indicated generally by the reference character Il) is provided with two outside multi-contact simultaneously operable switch units or poles Il and l2 for closing and opening the main eld circuit and an intermediate multi-contact reversely operable switch unit or pole i3 for reversely opening and closing the eld discharge circuit. As shown, the switch unit Il is of standard form having a movable insulating link l5 operating a plurality of movable contact iingers I6 into and out of wiping engagement with the cooperating contacts Il. The movable contact fingers i6 are pivotally mounted at their lower ends on a current conducting pivot pin (like pin 42 shown in Fig. 4) extending between the side walls of the molded base I8. The cooperating contacts I 'l also are pivotally mounted as more clearly shown in the enlarged View of Fig. 2, each Contact l1 being formed with a pivotal bearing projection 2Q of substantially semi-cylindrical form for seating in the open groove 2| formed in the inside surface of the J-shaped conducting member 22 to provide extended pivotal movement of the cooperating contact nger il as indicatedy by the dotted lines in Fig. 2. Each cooperating contact Il is biased into the path of its cooperating movable contact nger ll by means of a pin 23 sliding in a suitable opening 24 formed in the conducting member 23 and biased into engagement with the `linger Il by a compression spring 25. In this same way, the several cooperating contacts I7 of each pole of the breaker l0 may be of the same standard form and mounted in coaxial pivotal alignment and biased into the path of the cooperating movable contacts I6, which in turn may be of a standard form, for extended wiping engagement therewith as indicated in Figs. 2 and 3.

The insulating multiple contact operating switch link l5 of unit l l carries a cross shaft 21 that serves to close and open the switch contacts i6 upon opposite reciprocation thereof in the guide slots 26 formed in each of the side walls 3l and 32 of the operating mechanism indicated generally by the reference character 33.

f The cross shaft 2l also is connected through a link 23 to a pin 29 for operating an indicating mechanism that shows the open and closed position of the main switch contacts of poles II and l2 through the window 35. In the preferred form of breaker shown in Fig. 1, the switch operating mechanism 33 is of the improved trip-free toggle latch type described and claimed in Patent 2,549,441, filed by John A. Favre on September 23, 194'? and assigned to the present assignee, although it should be understood that the improved motion converting mechanism of the present invention may be used with other suitable forms of switch operating mechanism and switches if desired.

In the form of switch shown, the operating rod 21 is reciprocated inwardly in the slot 26 by a trip-free toggle latch mechanism-so as to close the switch upon turning the operating handle 35 a quarter turn to the left from the vertical position in which it is shown and is released for opposi-te reciprocation to the switch opening position to which it is biased as shown in Fig. 1 upon operation of the latch trip button 35. The operating handle 35 is rotatably mounted in the escutcheon plate 31 that is secured to the two side plates 3| and 32 by the mounting screws 38 and lthe side plates 3I and 32 in turn are secured to the switch units I I, I 2, and I3 by suitable mounting screws 39.

The reciprocating operating rod 21 spans the intermediate pole I3 and extends through a guide slot in the side wall 32 similar to the slot 25 and is connected to operate the movable contact fingers of the switch unit I2 by a link similar to the link I so that both of the main field switch units II and I2 are closed and opened simultaneously upon operation of the closing handle 35 and the opening trip button 35.

The intermediate discharge switch unit I3 is reversely opened and closed upon simultaneous closure and opening of the two outside main field switch units Il and I2 and the improved reciprocating to reverse rotary motion converting mechanism for accomplishing this result is shown in Figs. 4, 5, and 6. As shown in Fig. 4, the movable switch member I6 and the cooperating switch member I1 of the intermediate discharge switch unit I3 are of the same standard form employed in the main eld switch units I l and I2 and this is also true of the parts that pivotally support and bias the cooperating contacts I1 in the manner previously described in connection with Fig. 2.

The movable switch contacts I6 of the discharge switch unit I3 are mounted in a contact carrier 4I that is rotatably mounted along with contacts I6 on pivot pin 42 that extends between the sides of the molded base I8 of the intermediate switch unit i3 coaxially with the pivoted contact ngers I6 for each outside pole I I and I2. In each pole, the standard contact ngers I6 may be biased into good electrical contact with the current conducting pivot pin 42 by means of a leaf spring 43 and thus removably mounted upon the pin 42 so as to permit ready renewal of any movable contact finger that may deteriorate in service due to arcing or burning.

As shown in Fig. 4, the contacts I3 and I1 of the intermediate discharge switch unit are closed into wiping engagement by means of a toggle formed by the link 44 that is pivotally connected with the pin 45 mounted upon and extending from the contact carrier 4I and the double link 46 that is pivotally mounted upon the iixed pin 41 and connected with link 44 by means of pin 48. The toggle formed by the links 44-46 is biased to its extended position in which it is shown in Fig. 4 by means of a pair of tension biasing springs 49 and is collapsed to open the switch as shown in Fig- 5 by means of a lever 5I) that is centrally pivoted on the fixed pivot pin 5I and has a cam motion sliding operating connection 52 formed by slot 54 at one end thereof with the toggle link 43 and also a lost motion sliding connection with the reciprocating switch operating rod 21 formed by the enlarged opening 55 at the other end thereof.

As shown more clearly in the partial end view of Fig. 6, the double pivot link 45 has its two spaced-apart halves on opposite sides of the centrally pivoted lever 50 that is provided with an enlarged opening 53 for permitting the fixed pivot pin 41 of the double toggle link 45 to extend through the lever 5G without interfering with the pivotal movement thereof. The lower end of the lever 5I) is provided with the slot 54 for receiving therein an eccentric 55 that is adjustably clamped between the two halves of the toggle link 45 so as to form an adjustable sliding cam motion operating connection between the nxedly pivoted toggle 46 and the Xedly pivoted lever 55. The fixed pivot pin 41 for the double toggle link 45 is mounted in the side walls 51-58 of the U-shaped bracket 59 that is secured to the base I8 by suitable holding-down bolts 6B. The xed pivot pin 5I of lever 5D is similarly mounted between the side walls of the mounting bracket 53 and the two biasing springs 49 each have one end thereof engaging with a pin 6I that also extends between the side walls of the bracket 59 and the other ends of the springs are hooked around the bolt 53 that serves adjustably to clamp the eccentric 55 between the halves of the double toggle lever 46. The two centering bushings 54 serve to maintain the double toggle link 46 as well as the lever 5! in their properly aligned operating positions between the walls 51-58 of the mounting bracket 59.

Operation As schematically shown in Fig. '7, the two outside poles I I and i2 of the triple-pole eld switch lil when closed serve to interconnect the eld winding 55 to be energized from suitable supply lines LI, L2, the energizing circuit extending from supply line LI through conductor S6, pole II, conductor 51, eld winding 65, conductor 68, pole I2, and conductor 69 to the other supply line L2. As previously indicated, the poles Il and I2 are closed by rotating the handle 35 a quarter turn to the left so as to reciprocate operating member 21 in the guide slots and thereby exert a force through the links I5 to operate the movable switch contacts I5 into wiping engagement with the cooperating switch contacts I1. During the pivotal movement of the movable switch contacts into initial engagement with the cooperating contacts, the reciprocating rod 21 moves across the enlarged lost motion opening 56 to take up the lost motion and thereafter rotates the lever 55 about its fixed pivot 5I in a clockwise direction and thereby through the cam motion sliding connection 52 provided by slot 54 effects a corresponding clockwise rotation of the toggle link 46 so as to quickly collapse the toggle and open the intermediate pole of the switch I3 during the wiping engagement of the two outside poles II and l2. As a result, the circuit through the field discharge resistor 1I is opened by the intermediate pole I3 only after `the energizing circuit for the seid winding es is closed by the outside poles II and I2.

When the breaker Iii is tripped by operation ot the latch trip push button 3e so as to open the outside poles Il and I2 as shown in Fig. 8, the reciprocating rod 21 will move quickly in the opposite direction in the guide slots 35i and the two springs et will cause the lever be to immediately follow the motion of the reciprocating rod 29 so as to reset the toggle formed by the links llt and i4 and thereby reclose the intermediate pole I3 as indicated in Fig. 8 before the contacts of the two outside poles II and I2 are moved out of wiping engagement. In this way, the extended wipe provided for the outside poles I I and I2 insures that the intermediate pole I3 is closed to connect the discharge resistor 'II across the neld winding e5 before the opening of the outside poles il and I2 can be effected.

What I claim as new and desire to secure by Letters Patent of the United States is:

l. A sequential switch mechanism having in combination a pair of coaXially pivoted separately operable switches, each having an operating link pivotally connected thereto, and sequential 0perating means therefor including a reciprocating operating member pivotally connected to one of the links for closing and opening the corresponding one of the switches and having independently pivoted double lever reverse rotary motion converting connections with the other link for reversely opening and closing the other switch upon opposite reciprocation of the operating member.

2. A sequential switch mechanism having in combination a pair of coaxially pivoted separately operable switches, each having an operating link pivotally connected thereto, and sequential operating means therefor including an operating rod slidably mounted for lateral reciprocation and having a pivotal connection with one link for closing and opening the corresponding one of the switches and an independently pivoted double lever reverse rotary motion converting toggle linkage connection with the other link for reversely opening and closing the other switch upon opposite reciprocation of the operating rod.

3. A sequential switch mechanism having in combination a pivotally mounted switch having a coaxially pivotally mounted switch in alignment on each side thereof and sequential operating means for said switches including a laterally reciprocable operating rod spanning the intermediate pivotally mounted switch and having a separatelink connection for closing and opening each of the coaxially pivoted outside switches simultaneously and having a reciprocating to reverse rotary motion converting toggle linkage connection for reversely opening and closing the intermediate pivotally mounted switch upon opposite reciprocation of said operating rod.

4. A sequential switch mechanism having in combination a pair of separately operable switches, means including a movable operating member having connections for closing and opening one of the switches upon opposite movements of the member, means including a toggle having a biasing spring for normally extending the toggle to close the other switch and a centrally pivoted lever having one end provided with a cam motion connection with one of the toggle links and the other end provided with a lost motion connection with the movable member for collapsing the toggle to open the other switch when the one switch is closed.

5. A sequential switch mechanism having in combination a pair of aligned separately operable switch members, each having an operating link pivotally connected thereto and each having a movably mounted cooperating contact biased for wiping engagement and disengagement therewith, sequential operating means including a reciprocating operating member having a pivotal connection with one link for effecting wiping engagement and disengagement of the corresponding one of the switch members with .its cooperating contact upon opposite reciprocation of the operating member and having independently pivoted double lever motion reversing connections with the other link for reversely eiecting wiping disengagement and engagement of the other switch member with its cooperating contact during the opposite wiping operations of the one switch member.

G. A sequential switch mechanism having in combination a pair of coa-Xially pivoted separately operable switch members, each having an operating link pivotally connected thereto and each having a movably mounted cooperating contact biased for wiping engagement and disengagement therewith, and sequential operating means including a reciprocating operating member having a pivotal connection with one link for effecting wiping engagement and disengagement of the corresponding one of the switch members upon opposite reciprocation of the operating member and independently pivoted double lever reverse rotary motion converting toggle linkage connection with the other link for reversely effecting wiping disengagement and engagement of the other switch member with its cooperating contact during the opposite wiping operations of the one switch member.

7. A sequential switch mechanism having in combination a pair of coaxially pivoted separately operable switch members, each having an operating lever pivotally connected thereto and each having a pivotally mounted cooperating contact biased for wiping engagement and disengagement therewith, sequential operating means including a reciprocating opera-ting member having a pivotal connection with one link for effecting wiping engagement and disengagement of the corresponding one of the switch members upon opposite reciprocation of the member, and means including a first centrally pivoted lever pivotally connected at one end with the other link to form a toggle and having a biasing spring connected to the other end of the rst lever for normally extending the toggle to close the other switch member and a second centrally pivoted lever having one end provided with a cam motion connection with said other end of the toggle lever and the other end provided with a lost motion connection with the reciprocating member for collapsing the toggle to effect wiping disengagement of the other switch member during the wiping engagement of the one switch member.

3. In combination, a pivotally mounted switch member having opening and closing mechanism including a reciprocating operating member, a coaxially pivotally mounted switch member having reverse opening and closing mechanism including a lever pivoted intermediate its ends and having a lost motion connection with said reciprocating operating member at one end of the lever, a second lever pivoted intermediate its ends and having a cam motion connection between one end thereof and the other end of the rst lever, a link interconnecting the other end of the '2' second lever with the coaxially plvotally mounted switch member to form a toggle for operating said switch to the closed position when the toggle is extended and to the open position when the toggle is collapsed, and a spring connected to bias the toggle to its set position.

9. A switch unit having in combination a pivotally mounted switch member, a reciprocating operating member therefor, a lever pivoted inrtermediate its ends and having a lost motion sliding connection with said operating member at one end of the lever, a second lever pivoted intermediate its ends and having a cam motion .sliding connection between one end thereof and the other end of the rst lever, a link interconnecting the other end of the second lever with the pivoted switch member to form a toggle for operating the switch to one position when the 8 toggle is extended and its other position when the toggle is collapsed, and a spring connected to bias the toggle to its extended position.

PHILIP C. NETZEL.

REFERENCES CITED The following references are of record in the le of this patent:

UNITED STATES PATENTS Number Name Date 522,851 Peirce July 10, 1894 641,157 Shepard Jan. 9, 1900 2,204,393 Atwood June 11, 1940 2,328,318 Wood Aug. 31, 1943 2,329,003 Seaman Sept. '7, 1943 2,473,992 Fowler June 21, 1949 

